This application claims the priority of Korean Patent Application No. 2003-53888, filed on Aug. 4, 2003, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein in its entirety by reference.
1. Field of the Invention
The present invention relates to an apparatus for and a method of converting a picture format, and more particularly, to an adaptive de-interlacing apparatus and method based on a phase corrected field corresponding to a predetermined interlaced field by which an input interlaced picture signal is converted into a progressive picture signal.
2. Description of the Related Art
A general television picture signal is compressed in the frequency domain using an interlacing method to form one frame with two fields. However, lately, a picture is commonly displayed on a personal computer (PC) and a high definition television (HDTV) using a progressive method. Therefore, to display an interlaced picture, a progressive scanning should be performed to generate picture lines, which are omitted in the interlaced picture, with an optional method. This is realized using a de-interlacing method.
FIG. 1 is a drawing to describe a conventional video data de-interlacing method.
With reference to FIG. 1, during de-interlacing, a field including only all vertically odd or even samples is converted into a frame. At this time, an output frame F0({right arrow over (x)},n) is defined by Equation, 1.
                                          F            0                    ⁡                      (                                          x                ->                            ,              n                        )                          =                  {                                                                      F                  ⁡                                      (                                                                  x                        ->                                            ,                      n                                        )                                                                                                                    (                                                                  y                        ⁢                                                                                                  ⁢                        mod                        ⁢                                                                                                  ⁢                        2                                            =                                              n                        ⁢                                                                                                  ⁢                        mod                        ⁢                                                                                                  ⁢                        2                                                              )                                    ,                                                                                                                          F                    i                                    ⁡                                      (                                                                  x                        ->                                            ,                      n                                        )                                                                              otherwise                                                                        [                  Equation          ⁢                                          ⁢          1                ]            
where {right arrow over (x)} denotes a spatial position, and n is a field number. Also, F({right arrow over (x)},n) is an input field, and Fi({right arrow over (x)},n) is an interpolated pixel.
FIG. 2 shows a conventional de-interlacing method based on motion compensation. In this method, motion information of a picture is extracted to interpolate vacant lines of a present field, and then the vacant lines of the present field are interpolated using pixels of a preceding field or a next preceding field based on the extracted motion information.
In the de-interlacing method based on an MC, it is assumed that a motion vector between adjacent even parity fields or adjacent odd parity fields has uniform velocity, and then a field is inserted in the middle position between two adjacent even or odd parity fields.
The video line interpolating method using an MC is disclosed in U.S. Pat. No. 6,233,018.
However, since a moving picture does not always have the uniform velocity, and the position of an inserted field is not right middle position between two adjacent fields with the same phase, a serration phenomenon appears, which degrades the quality of the moving picture.